This is of particular interest in intermittent fasting protocols, where one might want to have two feeding episodes, say post noon workout and dinner.
Your body will absorb nearly all the protein that you consume in a meal. Depending on the source, your body will absorb anywhere from 1.3g per hour on the low side (Eggs come in around 3g/hour), up to 8-10g per hour on the high side (whey protein). (Unfortunately, I do not have access to anything but the abstract rather than the full study). Protein stays in the digestive tract for quite a while, which leads to the full (or nearly so) absorption of ingested protein.
The study also appears to address other factors in excessive protein consumption, such as excreting the excess nitrogen and other wastes associated with protein digestion and utilization. However, I cannot confirm since I don't have a source for the full article.
In the abstract they suggest a maximum safe upper limit of:
25% of energy requirements at approximately 2 to 2.5 g x kg(-1) x d(-1), corresponding to 176 g protein per day for an 80 kg individual on a 12,000kJ/d diet. This is well below the theoretical maximum safe intake range for an 80 kg person (285 to 365 g/d).
Note that they give it as a 12,000kJ diet which is in the neighborhood of 2800 calories a day, which is fairly substantial in the average non athlete.
For the question that you cite, I think you're misinterpreting it a bit. You can absorb more, but it may not be beneficial. The cited article in that question reviews a few different studies, and concludes that .75g/lb/day is the highest limit that benefits structural changes (i.e. muscle building). You can eat more safely, and absorb more safely, but it may not really be of any benefit.
Examine.com concludes that,
For maximal stimulation of muscle protein synthesis, aim for a per-meal dose of quality protein (such as can be found in meat, eggs, and dairy) of 0.4–0.6 g/kg [and immediately after resistance training]. Higher doses will not be wasted and are probably necessary when eating mixed meals that contain a variety of protein sources.
You may have heard that if you eat more than 30 grams of protein in one sitting, the “excess” will pass undigested, but that’s just a myth. It is however true that spreading your protein intake over a few meals, making sure that you meet your desirable minimal protein intake per meal with each meal, will generally result in greater lean mass and strength. A pragmatic review article suggests that, to maximize their lean mass, active adults should consume 1.6–2.2 g/kg/day spread across four meals (0.40–0.55 g/kg/meal).
After compiling various studies, fitness coach Jeff Nippard concludes that muscles can absorb more protein,
- in individuals with more muscle
- when more muscle is trained (whole body vs. legs)
- in older individuals, due to anabolic resistance
Intermittent fasters don't seem to be affected by their feeding schedule, and literature confirms it (6:05 in the video), but the study quality was low, and they used low total daily protein amounts. The body has an unlimited capacity to absorb amino-acids, but how much is utilized for muscle synthesis, is different. Absorbed protein may also limit muscle protein breakdown. Optimally, target 1g/lb of body mass, spaced over 4-5 meals.